1. Field of the Invention
This invention relates to decorative laminates. More particularly, this invention relates to core stock paper for use in decorative laminates which may be newsprint, newsprint pulp, recycled waste newspaper or repulped newsprint.
2. The Prior Art
Generally, saturating papers have been manufactured from hardwoods and pine, or a combination of the two in various proportions by the kraft pulping process. Hardwoods have customarily been considered cheaper sources of wood for the papermaking process and are desirable for saturating paper because of their excellent absorption qualities. A hundred percent hardwood pulp, although excellent from a saturating viewpoint, is not desirable on the papermaking machine; because the slurry is difficult to maintain at high speeds. Furthermore, a sheet made from all hardwood pulp will tend to pull apart when saturating. Another objection to hardwood pulp is "picking". Picking is the term used for the mechanism of a particle of wood fiber stuck on the roller causing a continuous imprinting of an image on all the paper that passes this point of the roller.
Picking and slow machine speeds are a result of the shortness of the hardwood fibers. A solution to these problems is to add longer stable pulp, such as pine, to the pulp slurry. The longer stable gives the webbing strength and reduces picking greatly, thereby enabling faster running of the paper on a given machine with less defects but is considerably more expensive. Although a solution to problems of runnability and picking is found through the use of pine, others have looked to less expensive core materials to solve the problem but have had to use additional processing steps, such as pretreating with cationic surface active agents as was done in U.S. Pat. No. 2,658,828 to Pattiloch.
It should be kept in mind that the core sheets must meet several stringent requirements. The core sheet must be strong enough to go through the resin solution. The core sheet must be absorbent enough to pick-up and hold resin. The impregnated core sheet must reinforce the laminates and yet have good dimensional stability. And the core sheets must allow bending and not cause excessive warping or deformation. Thus, not every sheet can meet these requirements.
It is, therefore, the general object of this invention to provide a suitable core stock paper containing newspaper.
Another object of this invention is to provide a saturating paper that will be sufficiently flexible so as to be operable in various papermaking machines without worry as to the breaking of the webbing or the picking of the short fibers on the rollers.
Still another object of this invention is to replace a portion of the hardwood or pine furnish of a core sheet with a less expensive material and still meet N.E.M.A. specifications.
Other objects, features and advantages of this invention will be evident from the foregoing detailed description.